1. Field of the Invention
This invention relates to overrunning coupling and control assemblies, each of which includes apparatus having a latching mechanism.
2. Background Art
One-way clutches are commonly employed in automatic transmissions for automobiles. A one-way clutch allows a first clutch plate to free-wheel in a first rotational direction relative to a second clutch plate, and to clutch in a second rotational direction. Examples include roller clutches and sprag clutches.
It may be desirable to have the one-way clutching mode operable only upon demand, such that it is in free-wheeling mode in both directions until the one-way clutching is selectively actuated. There are different means of selecting when the free-wheeling stops and one-way clutching begins.
U.S. Pat. No. 7,258,214 discloses, with reference to FIG. 1, a pocket plate, generally indicated at 10, of a planar or overrunning coupling or clutch assembly, generally indicated at 12. A driving coupling or notch plate, generally indicated at 14, is nested within the pocket plate 10. The driving notch plate 14 is to be drivably connected to a torque input shaft (not shown). This driving connection is established by internal splines 16 formed on the driving notch plate 14, which drivably engage external splines on the input shaft. The pocket plate 10 is provided with external splines 18.
An actuator (not shown) may be drivably connected to a slide or control plate, generally indicated at 20, via a slide plate fork 22, which is secured to a tab 23 of the control member or plate 20, thereby causing the control plate 20 to be adjusted angularly with respect to the axis of the input shaft (which corresponds to a first axis 24 about which the plates 14 and 20 are rotatable. The control plate 20 is disposed between the plates 10 and 14 for limited angular rotation relative to the plates 10 and 14. The plate 14 can free-wheel in both angular directions about the axis 24 relative to the plate 10. The bi-directional free-wheeling motion is achieved in an operating mode when the actuator adjusts the angular position of the control plate 20 relative to the pocket plate 10 (via the fork 22) about the axis 24 to a position (i.e., overrun or disengaged position). An angular position (i.e., locked or engaged position) of the control plate 20 relative to the pocket plate 10 is also provided.
U.S. Pat. No. 7,344,010 discloses in its FIG. 1 (labeled as FIG. 2 in this application) a pocket member or plate, generally indicated at 10, of a planar or overrunning coupling or clutch assembly, generally indicated at 12. A coupling or notch plate, generally indicated at 14, is nested within the pocket plate 10. The notch plate 14 is to be connected to a part (not shown) via internal splines 16 formed on the notch plate 14, which engage splines on the part. The pocket plate 10 is provided with external splines 18. An actuator (not shown) may be drivably connected to a slide or control element or plate, generally indicated at 20, via a slide plate fork 22, which is secured to a tab 23 of the control member or plate 20, thereby causing the control plate 20 to be adjusted angularly with respect to a first axis 24 about which at least one of the plates 14 and 20 is rotatable. The control plate 20 is disposed between the plates 10 and 14 for limited angular rotation relative to the plates 10 and 14.
U.S. Pat. No. 7,484,605 discloses in its FIGS. 1-3 (labeled as FIGS. 3-5, respectively, in this application) a pocket plate or inner member, generally indicated at 10, of a overrunning radial coupling or clutch assembly, generally indicated at 12. An outer member or notch plate, generally indicated at 14, is mounted for rotation about a first axis 16 and is located adjacent the pocket plate 10 in radially inner and radially outer relationship. The notch plate 14 may be drivably connected to a source of torque (not shown). This driving connection is established by external splines 18 formed on the notch plate 14, which drivably engage splines on the source torque. The pocket plate 10 may be stationary or rotatable about the first axis 16 and is provided with internal splines 19. An actuator (not shown) may be drivably connected to a slide or control element or plate, generally indicated at 20, via a slide plate lever 22, which is connected to the control member or plate 20, thereby causing the control plate 20 to be adjusted angularly with respect to the first axis 16 (about which the plates 14 and 20 are rotatable). The control plate 20 is disposed between the plates 10 and 14 for limited angular rotation relative to and between the plates 10 and 14. The plate 14 can overrun or free-wheel in one angular direction about the axis 16 relative to the plate 10. The one-way free-wheeling motion is achieved in an operating mode when the actuator adjusts the angular position of the control plate 20 relative to the pocket plate 10 (via the lever 22) about the axis 16 to a first angular position (i.e., one-way overrun or disengaged position).
U.S. Pat. No. 6,290,044 discloses a selectable one-way clutch assembly for use in an automatic transmission comprising a strut plate rotatable about a central hub and having pockets and struts mounted therein for pivotable rotation. A selecting plate concentrically located about an activator hub has teeth extending axially inboard and configured to fit in the apertures in an activator plate. A turning device is selectively operable to activate a one-way clutching mode by rotating the pin of a control plate to disengage selecting cams and displace selecting plate teeth inboard beyond the inboard face of the activator plate wherein the struts catch the teeth when the strut plate assembly is rotated in a clutching direction. The turning device includes a hydraulic actuator having an actuating member with a small radial slot through which the pin extends, and a pressurizeable chamber. Upon pressurization, the actuating member is displaced along a tangent of the control plate and thus the pin is displaced rotationally. The actuator includes an actuator release spring to bias and return the actuating member towards the chamber. The turning device may also include an electrical solenoid to displace an actuating member as described above.
Other U.S. patent publications which disclose controllable or selectable one-way clutches include U.S. Pat. Nos. 5,927,455; 6,193,038; 6,244,965; 7,198,587; 7,275,628; and 7,464,801, and U.S. Publication Application Nos. 2007/0278061; 2008/0110715; 2008/0169166; 2008/0185253; 2008/0223681; 2009/0159391; and 2009/0211863.
For purposes of this application, the term coupling should be interpreted to include clutches or brakes wherein one of the plates is drivably connected to a torque delivery element of a transmission and the other plate is drivably connected to another torque delivery element or is anchored and held stationary with respect to a transmission housing. The terms coupling, clutch and brake may be used interchangeably.
One problem associated with such controllable one-way coupling assemblies is that the one-way clutch may inadvertently change (such as due to parasitic losses) from its overrun position or mode to its locked position or mode especially when the ambient temperature is well below 0° F. due to the highly viscous hydraulic fluid in the one-way clutch. Such a change could cause the clutch to fail.